DESCRIPTION (Applicant's Abstract): This research will focus on preschool children's awareness of mental imagery. Previous research suggests that preschool children have a global metacognitive deficit in that they are generally incapable of reflecting on and talking about their thought processes. The hypothesis guiding the proposed research is that preschool children often do have conscious access to their mental activity when they are actively engaged in a task, especially if the task requires visual imagery. This hypothesis was supported in preliminary studies in which preschoolers played a computer game in which the mental rotation of a visual image was an optimal strategy. Almost half the 4-year-olds and most of the 6-year-dds explained their successful performance by referring to thinking" or imagination" or by explicitly describing mental rotation. This investigation will replicate and extend these initial findings. Children will have multiple sessions with the computer game. The sequence will begin with sessions that involve no instructions to use mental rotation and culminate in sessions that will include direct training and guided practice in the use of mental rotation. In conjunction with these procedures there will be a corresponding progression of more direct and specific questions about children's mental activity during the task. The task, procedures, and questions are thus designed to detect different levels of metacognitive ability in young children. They embody the principle of "progressive scaffolding" in that children will be given the minimum amount of instruction, training, and questioning necessary for optimal performance This research should contribute to our basic understanding of the development of mental imagery and metacognition. Psychotherapeutic techniques using visual imagery are now routinely employed with children, yet there is little detailed knowledge from basic research to guide clinical uses of imagery with children. By investigating children's conscious awareness of mental imagery, this research should yield information that may prove useful to clinicians in their use of imagery techniques with children.